9, 16, 18, 24, 31 October 7pm; 7, 12 November 7pm; 2 November 3pm

Director Christopher Alden
Rosemary Joshua (Partenope)
John Mark Ainsley (Emilio)
Patricia Bardon (Rosmira / Eurimene)
Christine Rice (Arsace)
Iestyn Davies (Armindo)
James Gower (Ormonte)

English National Opera chorus and orchestra
Christian Curnyn (conductor)

£10-£76

Ritualistic, formal, often plain bizarre to modern eyes, 'opera seria' is connoisseur's stuff. Think county cricket, grandmaster chess, sumo wrestling, Latin homework. It's a rarefied world of ancient gods and goddesses, kings and queens; of battles and love triangles and da capo arias, in which the first bit is repeated with variations, in case you didn't get it first time. A da capo aria, you see, is one in which the first section is sung again, only with extra vocal decorations.

Then, of course, there are the castratos. Sneered at and celebrated in equal measure in their time - a bit like Premiership footballers today - the star castrato was a boon to the composer: with the high supple voice of a woman but the trumpet-like power supplied by a larger male frame, he could pour out beautiful and agile melody over the top of a chugging baroque orchestra. And that remote, unnatural quality of the voice was just right for suggesting some uber-being: an ancient god or king. The last castrato died shortly after the phonograph came in (Moreschi, his name was; hard to judge through the chip-shop crackles, but he doesn't sound much good). Now their roles are sung by counter-tenors, men whose contrast between their speaking voice and eerie falsetto singing voice draws a fascinated following of their own.

Such fascinated followers, and lovers of opera gender-bending, are well served by this stylish and outstandingly sung new ENO production. One of Handel's more obscure pieces, it's that odd thing, an opera seria comedy: a hectic love quadrilateral of gods'n'goddesses, its vertices being a woman, a man singing counter-tenor, a man who is sung by a woman, and a woman who is a woman but disguised as a man.

Yes, it's confusing stuff, a confusion suitably compounded by the similarity of the three high voices in tone and their appearance, in similar but colour-coded 1920s suits and moustaches, but stick with it and it becomes clear, and it all ends happily. The music is accomplished, crystal-clear, and dazzling as ever. Handel fans will revel in the master's craftsmanship and accessible invention. It's cleanly and finely played too, with the crispy topping of period twangers such as theorbo. Some may feel Christian Curnyn is a bit brisk at times, if they're used to more expansive, upholstered slow passages, and the fast bits proved a challenge for the singers in those florid ornamental runs. But for me it worked, and when an opera clocks in at over three hours, there's no room for dawdling. (Two intervals; so time for two trips to the Chandos pub round the corner, with its Sam Smith's for under £2 a pint).